obsidian-second-brain

# Obsidian Second Brain > Claude operates your Obsidian vault as a self-rewriting knowledge base. An evolution of [Karpathy's LLM Wiki pattern](https://gist.github.com/karpathy/442a6bf555914893e9891c11519de94f): sources rewrite existing pages instead of just appending, contradictions reconcile automatically, and scheduled agents maintain the vault while you sleep. > Everything worth remembering gets saved. Every update propagates everywhere it belongs. --- ## Quick Start ### 0. Choose vault access method (in order of preference) Try these methods in order. Use the first one available: **Method 0 - SessionStart hook (if configured):** If `hooks/load_vault_context.py` is wired as a SessionStart hook in `~/.claude/settings.json`, `_CLAUDE.md` is injected into context automatically at session start. Skip step 1 only when the manual is actually in your context, not merely because the hook is configured. Claude Code caps hook context at 10,000 characters, so a larger manual cannot be injected; in that case the hook says so in as many words ("NOT loaded - read it") and you read the file yourself (#270). A vault whose `.claude/CLAUDE.md` holds `@../_CLAUDE.md` sidesteps the cap entirely - Claude Code imports that natively at any size. To wire it: `bash scripts/setup.sh "/path/to/vault"`. If another Obsidian plugin also holds a SessionStart hook, the injected context opens with a precedence note naming it (#300). Claude Code runs every SessionStart hook and adds each output here...